找考题网-背景图
单项选择题

In Sections A, B and C you will hear everything once only. Listen carefully and then answer the questions that follow.
SECTION A TALK
Questions 1 to 5 refer to the talk in this section. At the end of the talk you will be given 15 seconds to answer each of the following five questions. Now listen to the talk.

The technology to make machines quieter()

A.has been in use since the 1930’s.
B.has accelerated industrial production.
C.has just been in commercial use.
D.has been invented to remove all noises.